Tests seem to depend on Encode.pm
See for example
http://nntp.x.perl.org/group/perl.cpan.testers/3067949
Since perl 5.6.2 comes without and even 5.8 users can opt out of the
Encode module, it should find its way into the PREREQ_PM declaration.
If there are other reasons to not support 5.6.2 directly, you could
probably consider adding a "use 5.008" to your Makefile.PL to get rid of
FAILs from an unsupported version of perl. If you haven't seen the
cpantesters wiki page yet, here it is:
http://wiki.cpantesters.org/wiki/CPANAuthorNotes
Thanks,